clomazone (Command 3ME)
Rate 0.5 lb ai/A (21.3 oz/A)
Time Apply to soil before or after seeding but before crop emerges.
Remarks Crop rotation restrictions may be up to 16 months, depending on rate. Sensitive crops include tomatoes and wheat. Some temporary chlorosis of green peas may occur. Avoid overlaps while spraying.
Caution Do not mix or apply within 1,000 ft of landscapes, orchards, vegetable gardens, berry patches, or property lines to prevent chemical trespass. Evidence west of the Cascades suggests that lower rates of 0.25 to 0.33 lb ai/A (11 to 14 fl oz/A) controls susceptible weeds in early spring. Do not graze cover crops, or harvest food or feed within 9 months of application. Do not allow livestock to graze on treated pea vines or vine trash.
Site of action Group 13: inhibits DOXP synthase
Chemical family Isoxazolidinone
halosulfuron-methyl (Sandea)
Rate 0.023 lb ai/A (0.5 oz/A)
Time Preemergence
Remarks Do not apply more than 0.5 oz of Sandea per acre per year. Not all pea varieties have been tested for tolerance. Under adverse growing conditions, maturity of the treated crop may be delayed, affecting harvest date, yield, and quality. For untested varieties, a small area of the field should be sprayed to determine potential sensitivity to its use. See label for significant crop rotation restrictions for this herbicide.
Caution Application of halosulfuron may cause significant, temporary stunting and delay maturity of peas resulting in delayed harvest. This product is available to the end-user/grower solely to the extent that the benefit and utility, in the sole opinion of the end-user/grower, outweigh the extent of potential injury associated with the use of this product. Due to the risk of crop damage, all such use is at the end-use/grower's risk.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
imazethapyr (Pursuit and others)
Rate 0.0469 lb ai/A (3 fl oz/A Pursuit)
Time Apply after planting but before crop emerges.
Remarks Apply only once per year.
Caution Do not apply postemergence. Crop rotation is 18 months for sweet corn, oat and sorghum, and 26 months for potato.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
linuron (Lorox DF50)
Rate 0.5 to 1 lb ai/A (1 to 2 lb/A Lorox) depending on soil texture and OM content
Time Post plant, preemergence to crop.
Remarks Make only a single preemergence application of Lorox DF per season and do not exceed 2 lb of Lorox DF in any application. Lorox must be activated within 2 weeks of application for optimum control with rain or irrigation of 0.5 inch or more. Tankmix with other herbicides such as S-metolachlor to broaden spectrum.
Caution Do not exceed 2 lb Lorox DF in any application. Soybeans planted too shallow have increased potential for injury. Do not feed treated forage to livestock. Do not apply to sand or loamy sand soil types. Do not use on soils with less than 1% organic matter. Do not apply this product to dry peas through any type of irrigation system.
Site of action Group 7: photosystem II inhibitor
Chemical family Urea
metribuzin ((Tricor 4F, Glory 4L and others)
Rate 0.19 to 0.38 lb ai/A (6 to 12 oz/A Tricor 4F)
Time Apply once per season, soon after planting, and incorporate with irrigation or cross-harrow to ensure uniformity within top 1 to 2 inches of soil.
Remarks Adjust rates for soil texture and organic matter.
Caution Restricted-use herbicide in Washington. Do not use on coarse, sandy, or shallow soils, or on soils with less than 1.5% organic matter. Crop may be injured if heavy rain follows application. Do not apply more than 0.5 inch of irrigation within 1 month after metribuzin application, to avoid crop injury. Experience is lacking in western Oregon; try small areas before treating large acreages. Crop may be injured if plants are stressed by cold weather, poor soil fertility, and disease or insect damage. Will not control weeds resistant to triazine (atrazine) herbicides. Grazing is permitted 40 days after treatment. Certify that pea variety, location, and irrigation conditions are listed on the product label you purchase.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazinone
S-metolachlor (Dual Magnum, Brawl, Medal, and others)
Rate 0.95 to 1.91 lb ai/A (1 to 2 pints/A Dual Magnum), depending on soil texture
Time Apply preemergence behind planter and activate with moisture.
Remarks May delay maturity and/or reduce yields if soils are cold and wet after planting. Do not apply more than 2.0 pints/A during any one crop year.
Caution Restricted-use herbicide in Washington to protect surface and groundwater. Preharvest interval is 120 days for hay. Do not use for forage within 60 days following application.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Chloroacetamide
pendimethalin (Prowl H2O, Stealth, and other)
Rate 0.7 lb ai/A (1.5 pints/A Prowl)
Time Within 2 days after planting. Rate depends on soil texture.
Remarks Conventional tillage only within 2 days of planting.
Caution Do not apply more than once per season. Do not apply to pea forage, pea silage, pea hay, or pea straw grown for livestock feed.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
saflufenacil (Sharpen)
Rate 0.017 lb ai/A (0.75 fl oz/A Sharpen)
Time Apply early preplant, preplant incorporated, or preemergence for limited residual broadleaf weed control.
Remarks There are no university data for use of this product in the PNW. Sharpen controls mainly broadleaf weeds. Methylated seed oil (MSO) or crop oil concentrate (COC), at 1% v/v + ammonium sulfate (AMS) at 8.5 to 17 lb per 100 gal, are required for satisfactory control of emerged weeds. An early preplant application of Sharpen at 0.75 fl oz/A can be made prior to PPI or preemergence application. Sequential applications must be at least 30 days apart.
Caution Do not substitute a nonionic surfactant for MSO or COC as control of emerged weeds will suffer. Do not exceed 2.0 fl oz/A during the cropping season. Do not apply when the peas have reached the cracking stage, or after emergence, because severe crop injury will occur. Legume forage may be fed or grazed 65 or more days after application.
Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor
Chemical family Uracil
sulfentrazone (Aquesta 4F and several others)
Rate 0.07 to 0.19 lb ai/A (2.25 to 6.0 fl oz/A) depending on soil type and organic matter content
Time Pre-emergence
Remarks There is limited university data for use of this product in the PNW. Sulfentrazone controls mainly broadleaf weeds. In coarse-textured soils with < 1.5% organic matter, wait a minimum of 7 days after application before seeding. Do not incorporate into the soil. Do not apply if peas have emerged. Do not apply in extended periods of dry weather. Do not apply more than 0.1875 lb ai (6.0 fl oz) per acre per year.
Caution Use rate is inversely dependent upon soil pH. Use higher rates within the specified rate range with lower pH (< 7.0) and lower rates within the specified rate range with higher pH (> 7.0). Rotational restriction of 18 months for corn and 24 months for canola. Do not incorporate into the soil.
Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor
Chemical family Triazinone